squashfs-tools provides tools for creating and appending to (mksquashfs) and extracting (unsquashfs) squashfs filesystems.
Squashfs is a compressed read-only filesystem. It is intended for general read-only filesystem use, archival use (i.e. in cases where a .tar.gz file may be used, and in constrained block device/memory systems (e.g. embedded systems) where low overhead is needed.